Perforated, embossed film to foam laminates

ABSTRACT

An embossed film-to-foam laminate is provided having minute perforations through the film selectively distributed essentially along the sidewalls and valleys of the embossed pattern. The integrity of the laminated film material is retained on the crowns of the embossed patterned surface, since the perforations in the film material are mainly distributed on the sidewalls and valleys of the embossed pattern. The laminated product has a water-resistant and abrasion-resistant upper surface imparted by the film material on the crowns while the small perforations in the sidewalls and valleys permit sound to pass through the film and be exposed to the acoustical matrix of the open cell foam component of the laminate while impeding the penetration of liquids (e.g. water) through the film into the foam under the action of gravity. The film and/or the foam material are heated to supply adhesive material by melting or softening which serves to bond the film material to the foam.

RELATED APPLICATIONS

This is a division, of application Ser. No. 583,799 filed June 4, 1975,now abandoned, which is a continuation-in-part of U.S. Ser. No. 476,216filed June 4, 1974, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention concerns embossed film-to-foam laminate.

2. Description of the Prior Art

Flexible, open cell foam is known to have good acoustical properties.For many uses of such acoustical foam, such as wall panels, increaseddurability and aesthetics are desired. Previous attempts to increase thedurability and abrasion resistance of acoustical foam includedlaminating a protective sheet to the surface of the foam. However, theplacing of a protective sheet in front of a good sound absorbing foamsignificantly impaired the sound absorbing properties of the acousticalfoam. Examples of foam-to-sheet laminates are contained in U.S. Pat. No.3,454,413, issued July 8, 1969 to Philip Miller and U.S. Pat. No.3,425,882, issued Feb. 4, 1969 to Albert L. McConnell et al. In additionto laminating a cover sheet to the foam, such processes also imparted anembossed pattern to foam by a procedure known as "masking" during heatlamination. However, the sheet material was not adhered to the foam atmany locations because of the presence of a masking fluid. The abrasionresistance of such a laminate is much less because of the absence ofadhesive in parts of the embossed pattern.

Prior art relating to embossed, perforated laminates but not concerninglaminates having an acoustical foam backing is disclosed in U.S. Pat.No. 3,292,619. Also, embossed foam rubber-to-foam laminates aredisclosed in U.S. Pat. No. 2,752,279. However, in that disclosure theperforations continue through the foam with the sidewalls of theperforations covered by the film thereby impeding sound penetration intothe foam.

SUMMARY OF THE INVENTION

A perforated and embossed film-to-foam acoustical product is providedcomprising a protective film embossed and laminated to an acousticalfoam backing. The embossed pattern is composed of crowns, valleys, andsidewalls connecting the crowns and valleys. The upper surface of theacoustical foam is contoured according to the embossed pattern and theprotective film is adhesively attached to the upper surface of theacoustical foam and conforms to the embossed pattern. The film materialis perforated essentially on the sidewalls and valleys of the embossedpattern while the top surface of the laminate defined by the crowns ofthe embossed pattern is substantially impervious to liquids and resistsabrasion because the film on the crowns is essentially withoutperforations and adhesively attached to the acoustical foam backing. Theembossed surface of the laminate is substantially opened by theperforations to provide good acoustical properties but because of thesmall size of the perforations and their location predominately in thesidewalls and valleys, the embossed surface does not appear to haveperforations. Accordingly, acoustical properties are achieved withoutthe product having the usual acoustical appearance. A hydrophobic liquidis preferably coated on the surface of the film which enhances the waterresistance of the laminate and also masks imperfections in themanufacturing process. The laminate also exhibits an aesthetically selfhealing ability in which tears and punctures tend to be invisible.Preferably, the film is heat-deformed to generally contour to thecellular surface structure of the foam, especially on the crowns of theembossed pattern. The depth of the valleys is substantially less thanthe foam thickness, usually from 1/20 to 1/4 of the foam thickness. Thelaminate is useful as a sound absorbing surface such as a wall panel, aheadliner in motor vehicle or airplane passenger compartments, or insimilar uses requiring an acoustical surface that is abrasion resistantand has an upper surface that is cleanable with liquids such as wall orceiling panels in an elevator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of the laminated product.

FIG. 2 is a sectional view along line 2--2 of the product of FIG. 1.

FIG. 3 is an enlargement of the valley and its adjoining sidewalls ofthe embossed pattern shown in block 2 of FIG. 2.

FIG. 4 schematically depicts a process for producing the product of FIG.1.

FIG. 5 graphically depicts data contained in Table II.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

The perforated, embossed, acoustical laminate can be produced by aprocess comprising the steps of contacting a deformable film with asurface of an open cell acoustical foam, adhesively activating with heateither the film or the surface of the foam, mechanically pressing andembossing the deformable film at an elevated temperature and pressureinto the surface of the foam in a predetermined embossing pattern andsetting the adhesive film and/or foam material by cooling to bond thelaminate (usually accomplished when the laminate cools to about roomtemperature after embossing). The parameters of temperature, pressureand time (duration of the embossing or mechanical pressing) arecontrolled to obtain the required perforations. Specific values for thetemperature, pressure and time depend upon the specific materialsselected for the foam and film and the thickness of the film selected.

Any flexible open cell foam material may be employed in practicing thisinvention and preferably can be adhesively activated upon exposure toheat, including both foam type thermoplastic resins and foam typeelastomers. Examples of such suitable open cell foams are polyether orpolyester based urethane foams and foams from vinyl polymers such aspolyvinyl chloride and its copolymers. Many different types of flexibleopen cell foams having acoustical properties are known and the selectionof any particular one is not critical to the practice of this inventionand well within the abilities of those possessing ordinary skill in thefoam art.

The thickness, density, cell pore size and degree of cell openness ofthe foam are capable of wide variations with the selection of specificvalues for these parameters being dictated by the desired end use of theproduct with specific emphasis upon the acoustical properties desired.Particularly preferred are acoustically controlled foams such asflexible, open cell polyurethane foams especially those having a poresize from 10 to 90 PPI and a density from 1.5 to 6 lbs./ft.³.

The film material can be any deformable nonwoven substantially waterimpenetrable film such as a plastic sheet or even a metal foil such asaluminum foil. The selection of a specific film material in combinationwith the thickness of the film sheet must be such that the film willdeform and perforate under the mechanical pressure and elevatedtemperature encountered in the embossing step. Suitable film materialinclude any of the well-known thermoplastic and thermoset film formingmaterials that can be mechanically and/or thermally deformed into thevalley areas of the embossed pattern and which preferably softensufficiently during embossing to adhesively bond to the foam. Examplesof suitable thermoplastic film materials are natural substances such ascrude rubber and synthetic materials such as polyvinyl chloride, nylons,fluorocarbons, linear polyethylene, polyurethane prepolymer,polystyrene, polypropylene, cellulose acetate, cellulose nitrate andacrylic resin. Thermoset materials undergo some softening under mildheating prior to thermosetting or rigidification (usually caused bycross-linking) and are therefore suitable. Precautions should be takento prevent thermoset material from setting prior to embossing (which canbe easily controlled by adjusting embossing temperature and time).Examples of suitable thermoset film materials are polyesters such asMYLAR®, amino resins and silicones. Metal foils are also sufficientlydeformable to be suitable for use as the film material especially themetals which soften more readily when exposed to heat such as aluminum,aluminum alloy, tin and tin alloys. Preferred film materials arepolyesters, polyethylene, polyvinyl chloride, polypropylene,polyurethane, cellulose acetate, cellulose nitrate polystyrene andsimilar elastomeric materials. Particularly preferred is polyurethanefilm.

The sheet of deformable film material can vary in thickness with theselection of any particular thickness depending upon considerations suchas the durability and cleanability of the laminate surface desired, theplasticity of the material selected at elevated temperatures and themalleability of the material selected. The embossing of the deformablefilm material into the valleys of the foam is accomplished bymechanically impressing the embossed pattern into the sheet material andfoam simultaneously at elevated temperatures. In this way, the filmmaterial is both mechanically and thermally deformed into the valleyareas during embossing which, for practical and economic considerations,dictates a thin film thickness which facilitates the mechanicaldeforming of the film during embossing at the slight elevated embossingtemperatures employed. This practical thickness varies depending uponthe film material selected and would usually be in the area of afraction of a mil (e.g., 1/10 mil) to about 20 mils thick with fromabout 3 to about 8 mils preferred.

Normally, when placing such a film surface in front of a good soundabsorber such as the flexible open cell foam material employed, the goodsound absorbing properties of the open cell foam is significantlyreduced. This reduction in good sound absorbency is substantiallyeliminated by the present invention as shown in FIG. 5.

The embossing pattern can vary greatly, it being only necessary that thepattern contain crowns and valleys interconnected by sloping sidewallswith the depth of valleys and the slopes of sidewalls being sufficientto cause the film material to achieve the required degree of perforationduring the embossing step. Specific depths and slope angles can varysignificantly because particular selections which will result inperforations during embossing are interdependent with other parameterssuch as thickness and malleability of the film material employed, thetemperature of the film material achieved during embossing, the speedand the mechanical pressure of the embossing rolls because all of theseparameters affect the perforations obtained during embossing. Thosepossessing ordinary skill in the art and enlightened by the presentdisclosure could readily select among these parameters an operablecombination of embossing pattern, sheet material, foam, embossingtemperature, speed and pressure that will result in the perforationspredominantly on sidewalls and valleys of the laminated product. Higherembossing temperatures will also thermo-deform the sheet material and/orthe foam to cause the film material to contour to the cellular structuredefining the surface of the foam. Specific combinations of embossingpatterns, embossing depth, embossing temperature, film material andthickness are demonstrated in the examples.

The process parameters that can be used to control the embossing processincluding the approximate size and number of perforations in thesidewalls and valleys are; (1) the mechanical pressure inserted on thefilm and the foam; (2) embossing time (duration of embossing pressure);(3) embossing pressure; (4) film material characteristics; (5) foammaterial characteristics; (6) embossing pattern characteristics; (7)embossing temperature; and (8) embossing release agents, lubricants, andsimilar aids.

The interaction of the above parameters can be adjusted to produce alaminate of the present invention. Furthermore, many of the processparameters are interrelated and adjustments upon one parameter can beused to affect another parameter. Obviously, embossing time andembossing temperature are related in that higher embossing temperaturesusually permit shorter embossing times with other parameters heldconstant. Likewise higher embossing pressures normally permit lowerembossing temperatures or the same embossing temperature when thickerfilm materials or less malleable film materials are used or when thickerless flexible foam materials are used. Deep embossing patterns usuallyrequire higher temperatures, higher pressures and/or longer embossingtimes. With other parameters held constant deeper embossing patternstend to result in larger perforations, likewise higher embossingtemperatures or embossing pressures also tend to increase the size ofthe perforations.

For most materials embossing temperatures from about ambient conditionsto about 600° F are suitable with embossing temperatures of from about450° F to about 550° F preferred with polyurethane film embossed ontopolyurethane foam. Embossing pressures are usually not measured directlybut specified in terms of the gap between the embossing roll and theback-up roll shown in FIG. 4 (items 7 and 8). This gap which results inthe embossing pressure when the film and foam are fed between therollers can vary from a gap of about 0 (the rollers just touching) to agap of about 80% of the foam thickness. With one inch thick polyurethanefoam and 3.5 mil thick polyurethane film a gap of approximately 0.120inches is preferred with a gap of from about 8% to about 20% of the foamthickness being quite suitable, especially in combination withperipheral speeds for the embossing roll of from about 8 ft/min. toabout 100 ft/min. (foam speed through the gap).

Embossing release agents, lubricants and similar aids can be applieddirectly to the embossing roll 7 shown in FIG. 4 or they can be appliedto the upper surface of the film material 6 before, during or afterlamination. When a release agent such as dimethyl siloxane is applieddirectly to the embossing roll 7 it aids in the embossing process andrelease of the resulting laminate from the roll. In addition, a releaseagent can also result in a slight gloss to the laminated surface whichmasks manufacturing irregularities in the product. Furthermore, thelubricating and release agents are hydrophobic and a coating of suchagents on the embossed surface increases the hydrophobisity of thelaminated surface and results in water beading on the surface ratherthan passing through the perforations. In addition to dimethyl siloxanethere are many other known release agents and lubricants which could beused such as the many well known fluorocarbon release agents, light oilssuch as machine oils and the like. Preferred are the hydrophobiclubricants and release agents such as dimethyl siloxane fluorocarbons,light petroleum oils, silicone oils and the like.

The eight parameters discussed above can be controlled in the process ofmaking the laminate so that the resulting laminate has perforationsmainly in the valley and sidewall areas. In order for the laminates tohave good acoustics the size (width) of the holes (perforations) shouldbe from about 1/50 of an inch to about 1/500 of an inch across. Sincethe holes vary in size and configuration including shapes such ascircles, ellipses and slits, their size (width) is measured in terms ofthe longest dimension across the hole or perforation. A more accuratedetermination of pore size with respect to the functionality of theproduct in terms of acoustics can be determined by measuring thepermeability of the resulting laminate. The process parameters discussedabove should be adjusted particularly the embossing time, temperature,and pressure and the depth of the valleys in the embossing pattern sothat the size and number of perforations are sufficient to produce apermeability of the laminate of from about 3 cubic feet per minute persquare foot (ft³ /min. ft²) to about 100 cubic feet per square foot asmeasured on the Frazier High Pressure Differential Air PermeabilityMachine when operated according to the U.S. Department ofCommerce-National Bureau of Standards Research Paper RP1471 as publishedin Part of Journal of Research of the National Bureau of Standards,Volume 28, May 1942 in an article entitled "Improved Instrument forMeasuring the Air Permeability of Fabrics", authored by Herbert F.Schiefer and Paul M. Boyland and operated at 1/2 inch liquid pressurelevel and with the sample clamped with sufficient pressure to compressthe perimeter of the test sample to prevent by-pass of the air flow(usually a pressure sufficient to compress the foam from about 50% toabout 75% of its origianl height). When the film material (which priorto embossing had a permeability of essentially 0) has sufficientperforations in it so that resulting laminate has a permeability of fromabout 3 to about 100 ft³ /min. ft² then the laminated surface issufficiently opened to permit sound to pass through and be exposed tothe acoustical matrix of the foam backing. When the holes also numberfrom 30 to 1500 per square inch, the laminate is water resistant.Preferred is a permeability of from about 10 to about 30 ft³ /min. ft².

Measurement of the permeability of the laminated surface by directingair through a laminated surface and through the foam according to theFrazier test determines both the effectiveness of the size of the poresand the number of the pores in the laminated product since the air flowthrough the laminated surface must flow through the pores embossed intothe film during lamination.

The laminate also has the advantageous characteristic of beingaesthetically self healing. When the laminated surface is torn, such aswhen a jagged instrument is pulled across the laminated surface, thesurface tends to rip and tear predominantly in the sidewalls and valleysof the embossed pattern which is relatively weaker than the crowns.

A continuous pattern of sidewalls and valleys defining discretediscontinuance crown areas in the embossed pattern is depicted inFIG. 1. Because of the numerous perforations through the film located inthe sidewall and valley areas, the sidewalls and valleys aresubstantially weaker than the crown areas of the laminated surface.Tearing of the laminated surface tends to occur along the sidewall andvalley portions of the embossed pattern. Because of the flexible foambacking, the laminated surface tends to return to its shape prior totearing and since the tears are predominately located in the sidewallsand valleys they are hardly noticeable. Accordingly, a jagged tearthrough the laminated surface and into the flexible foam becomesessentially invisible when viewed by an unaided eye at a viewingdistance of one foot from the laminated surface after the laminatedsurface has returned to its configuration prior to tearing. This aspectof the laminated product is referred to herein as aesthetically selfhealing and is believed to be due to the "elastomeric memory" of thelaminate caused by the combination of a flexible foam and a flexiblefilm denser than the foam.

The novel and advantageous characteristics of the embossed laminateprovided by this invention can be best understood with reference to thefigures. FIG. 1 is a plan view of the laminated surface and shows thecrown area 1 of the embossed pattern, surrounded by the pattern formedby the deep recesses (valleys) 2 and the sidewalls 3. The perforations 4are shown on the sidewalls and valleys. The film 6 is shown with thetextured or patterned effect 10 on the crowns 1 caused by the deformingof the film to the cellular structure of the foam (the aspect isoptional).

FIG. 2 is a sectional view along line 2--2 of the laminated productshown in FIG. 1 and shows a sideview of the laminate. The valleys of theembossed pattern 2 and their depth below the crowns 1 can be seen inthis view. The steep slope of the sidewall 3 is also shown, which is apreferred embodiment for the embossing pattern because steep longsidewalls increase the amount of stretching and deformation the filmundergoes during embossing which increases the tearing and perforationsof the film along the sidewalls and valleys. Despite the tearing andperforating of the film, structural integrity is maintained on thecrowns. This results in weakened areas selectively located in thevalleys and sidewalls of the laminates. The perforations 4 are randomlydispersed on the sidewalls and valleys of the embossed pattern impressedinto the foam 5. The upper surface of the foam and the film 6 defined bythe crowns is water resistant because essentially all of theperforations are on the sidewalls and valleys. Furthermore, the smallinvisible size of the perforations in the sidewalls and valleys incombination with the use of silicone oils or other hydrophobiclubricants coated on the laminated surface makes the perforated portionof the laminated surface resistant to water penetration. In addition,the presence of the oily lubricant on the laminated surface masks minorimperfections and irregularities in the laminated surface which mayoccur during manufacture.

The perforations in the sidewalls and valleys are numerous and smallwhich result in sufficient porosity of the laminated surface to givegood sound absorbency but does not result in the usual appearance ofacoustical products which contain large holes. The small size of and theperforations also permit a cleanable water resistant surface.

The perforations are larger than the micropores found in syntheticleather products (poromerics) and smaller than macropores. Macroporesbeing defined as pores of sufficient diameter which overcome capillaryaction and permit water to pass through under the influence of gravity.The perforations through the valley and sidewall areas of the presentinvention generally vary in size (width) from about 1/50 of an inch toabout 1/400 of an inch. Such pore sizes are relatively small compared tothe holes normally encountered in acoustical panels and because of theirlocation predominantly in the sidewall and valley areas they areinvisible to the unaided eye when viewed at a distance of one foot orgreater. Accordingly the aesthetic aspects of the product have beenfreed from the necessity of having larger visible holes.

FIG. 3 is an enlargement of the area shown in box 2 of FIG. 2 andclearly shows the perforations 4 on the sidewalls and valleys.

FIG. 4 depicts a process for producing the laminate in which foam 5 isfed from a roll past a heat source 9 and through embossing roll 7 andback-up roll 8. The plastic film 6 is fed from a roller through theembossing rolls 7 and 8 while contacting the top surface of the foam.The desired pattern to be embossed is reproduced on the upper embossingroller 7 but in reverse (the valleys of the embossing pattern correspondto crowns on the embossing roller). A heat source 9 adhesively activatesthe top surface of the foam and/or the lower surface of the film. Theheat source could be the embossing roller 7 itself. Thermodeformablefilm will contour to the cellular structure of the foam during theembossing step which produces a slight irregularity to the film surfaceparticularly noticeable on the crowns as seen in FIG. 1, item 10. Theperipheral speed of embossing roller 7 is preferrably from about 8ft/min. to about 100 ft/min. When embossing roller is used as the heatsource it is preferably heated to a temperature of from about 400° F. toabout 600° F. A hydrophobic lubricant and release agent is preferrablyapplied to roller 7 which results in the coating of the film duringembossing.

FIG. 5 graphically compares the present invention with plain foam tofilm laminates (smooth) and foam to film embossed laminates but withoutperforations (perforations masked with paint).

EXAMPLE I

A 70 per inch (ppi) flexible open cell polyurethane foam sheet about 1inch thick was passed through embossing rolls as shown in FIG. 4 at aspeed of about 35 feet per minute (peripheral speed of roller 7).Simultaneously, a sheet of 4 mil thick TUFTANE® film (a polyester basedurethane film having a specific gravity of 1.21 and containingantioxidant and ultraviolet stabilizers sold by B. F. Goodrich ChemicalCompany as TF-312) was fed through the embossing rolls while contactingthe top surface of the foam. The upper embossing roll 7 was heated to atemperature of about 480° F. and had a contoured surface so as to embossa rosette pattern into the film and foam. The contour pattern on theroller consisted of about 25 protrusions per square inch having a depthof about 0.06 inches (hill to valley), and protrusions comprisingapproximately about 5% of the surface area of the roll and impress acorresponding depression or valley into the film and foam duringembossing. The resulting embossed laminate had a tough flexible topsurface comprising the TUFTANE® film strongly bonded to the foammaterial and containing perforations essentially along the sidewalls andvalleys of the embossed pattern impressed into the laminate by the upperembossing roll. The perforations numbered about 250 to 350 per squareinch and were mostly visible with light transmitted through thelaminated surface but were invisible with reflected light and were at adistance of one foot. The upper surface of the laminate defined by thecrowns of the embossed pattern was abrasion resistant andwater-resistant (it could be wiper vigorously with a wet cloth along theupper surface defined by the crowns without significant penetration ofwater into the foam). The acoustical properties of the foam base(reverse side of the product) and the acoustical properties of theembossed and perforated laminated surface of the product were testedaccording to ASTM Test C-384-58 entitled "Standard Method of Test forImpedance and Adsorption of Acoustical Materials by the Tube Method" atfrequencies of 0.3, 0.5, 1.0, 2.0, 4.0 and 6.4 Kilo Hertz. Results ofthe tests are listed in Tables I and II and are reported as per centacoustical adsorption (Table I) and acoustical index (Table II). Thistest and the acoustical adsorption of the material is mainly a surfacephenomenon and, therefore, the acoustical properties of both thelaminate side and the base foam side of the product were testedemploying a single sample of the laminated product and first testing theembossed and perforated laminated side and then reversing the product totest the acoustical properties of the foam base. This procedure insuredthat the acoustical test data for the foam based eliminated anydifference or variations in the acoustical properties of the foam fromone section of a sheet to another section of the sheet. The laminate ofExample I was torn along the laminated surface with a screw driver andwas punctured with a pencil. The tear and puncture holes wereessentially invisible after the laminated surface was smoothed by hand.

EXAMPLES 2-10

The procedure of Example 1 was repeated with different foam backingmaterials and different film materials. Examples 2-10 differ fromExample 1 in the following aspects: the pore size of the foam waschanged in Examples 2 and 3 from 70 ppi. to 60 ppi. (Example 2) and 50ppi. (Example 3); Examples 4, 5, and 7 duplicate Example 1 and areintended to show that while absolute values and acoustical absorptionmay vary due to differences between foam examples, the acoustical indexis consistently comparable and, therefore, the experimental data issignificant. Example 8 employs foam differing from the foam of Example 1in that the foam was treated prior to embossing according to a processthat fully reticulated the foam (dewindowed) but retained the 70 ppi.pore size, Example 9 employed the same foam as Example 1 but used a 1/2mil thick smooth aluminum foil as the deformable film material; Example10 employed a 1/2 mil thick texturized aluminum foil as the deformablefilm material.

The acoustical performance of the embossed and perforated laminate ofExamples 1-10 is reported in Tables I and II.

The data reported as Example 6 is a repeat of Example 3.

Comparative Examples

Comparative Example A employed the same foam and film material ofExample 1 but the laminated product was produced by smooth rolls ratherthan employing an upper embossing roll. This produced a nonembossed,nonperforated laminate with the TUFTANE® film material conforming to thecellular structure of and adhesively attached to the foam material.Comparative Example B employed the same foam and film material and thesame embossing rolls as Example 1. However, the embossed laminateproduct of Comparative Example B differed from the product of Example 1in the absence of perforations. In order to exactly duplicate theembossing pattern with the same materials of Example 1, the perforationscould not be avoided even with adjustments in the thickness of the filmmaterial and the temperature of the embossing roll and, therefore, inorder to produce the nonperforated embossed laminate for Comparative B,the perforations were closed by painting the embossed surface ofComparative B (5 coats of paint required to close the perforations).

Example 11

The procedure of Example 1 was repeated with the same foam and filmmaterial but employing an embossing roll having a diamond type patternconsisting of elongated diamond shaped protrusions on the upperembossing roll having a height of 0.050 inches and spaced approximately0.075 inches apart with approximately 27 protrusions per square inch ofthe embossing roll. The product was tested for its acoustical propertiesand the results reported in Table I.

Permeability tests were performed upon the laminates of Examples 1-11and comparative Examples A and B according to the Frazier test describedherein and the results are given in Table I. While Comparative Bexhibited some permeability, it is believed to be due to some opening ofthe paint masks during testing and not due to acoustically functioningperforations as shown by the acoustical performance data.

The best mode presently contemplated for practicing the presentinvention is by embossing a polyurethane film about 5 mils thick to aflexible open cell polyurethane foam having a pore size of about 70 ppi.and a thickness of from about 1/8 inch to about 3 inches thick andemploying an embossing pattern having a difference in height betweenvalleys and crowns of about 0.060 inches and with a sufficient numer ofcrowns and valleys per square inch of laminated product to result in atleast 10 and preferably between 30 and 1500 invisible perforations persquare inch of product.

By invisible perforations as used herein, is meant perforations thatcannot be seen with an unaided eye, except when the product isdelaminated and the film is viewed with a light source on the oppositeside of the viewer so as to highlight the perforations. Accordingly, theperforations are visible with light transmitted through the laminatedrather than with reflected or incident light. Delamination facilitatesthe transmission of light through the laminated surface. Theperponderance of the perforations in the laminates of Examples 1-11 wereinvisible.

Significance: The data reported in the Tables shows the acousticalperformance of the present invention in that the acoustical benefits ofthe foam backing are essentially retained while a water and abrasionresistant top surface is provided which usually interferes withacoustical adsorption (see Comparative A). Table I contains the percentsound absorption at various frequencies in Kilo Hertz for both the foambacking and the laminated surface. In order to eliminate acousticaldifferences between apparently similar foams, an acoustical index wascalculated from the sound adsorption data in Table I. The acousticalindex equals the percent sound absorption of the foam backing minus thepercent sound adsorption of the laminate surface. An acoustical index ofzero indicates perfect reproduction of the acoustical properties of thefoam backing while a negative index indicates a reduction in soundadsorption and a positive index indicates improvement.

                                      TABLE I                                     __________________________________________________________________________    Acoustical Properties - Frequency in kHz                                      Example                                                                            Base Foam   Laminate                                                     No.  0.3                                                                             0.5                                                                             1.0                                                                             2.0                                                                             4.0                                                                             6.4                                                                             0.3                                                                             0.5                                                                             1.0                                                                             2.0                                                                             4.0                                                                             6.4                                                                             Permeability                                     __________________________________________________________________________    1    18                                                                              25                                                                              68                                                                              98                                                                              76                                                                              94                                                                              16                             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                                                            15                                                                              20                                                                              34                                                                              60                                                                              73                                                                              47                                                                              99                                               9    15                                                                              30                                                                              73                                                                              70                                                                              44                                                                              48     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      98                                                                              23                                                                              33                                                                              76                                                                              85                                                                              68                                                                              69                                                                              21.9                                             11   15                                                                              22                                                                              50                                                                              90                                                                              74                                                                              95                                                                              24                                                                              28                                                                              63                                                                              95                                                                              75                                                                              98                                                                              46                                               Comp. A                                                                            22                                                                              38                                                                              86                                                                              95                                                                              77                                                                              78                                                                              11                                                                              56                                                                              28                                                                              40                                                                              22                                                                              21                                                                              0                                                Comp. B                                                                            19                                                                              26                                                                              63                                                                              99                                                                              82                                                                              96                                                                              * 33                                                                              20                                                                              33                                                                              25                                                                              20                                                                              3.87                                             __________________________________________________________________________

                  TABLE II                                                        ______________________________________                                        ACOUSTICAL INDEX                                                              (Base Foam - Laminate)                                                        Example                                                                              Frequency kHz                                                          No.    0.3     0.5     1.0   2.0   4.0   6.4                                  ______________________________________                                        1      -2      +1      +3    -5    +7    -5                                   2      +3      +4      +12   0     +3    -2                                   3      +2      +1      +4    0     +2    +5                                   4      -1      +2      +2    -6    +1    +1                                   5      +4      +4      +3    -2    +1    -2                                   6      +2      +1      +4    0     +2    +5                                   7      +6      +17     -3    +9    +2    -10                                  8      +3      +8      +18   +34   +21   -5                                   9      +15     +34     -12   -33   +12   -6                                   10     +8      +11     +27   -10   -7    -29                                  11     +9      +6      +13   +5    +1    +3                                   Comp. A                                                                              -11     +18     -58   -45   -55   -57                                  Comp. B                                                                              *       +7      -43   -66   -57   -76                                  ______________________________________                                    

What is claimed is:
 1. A method of producing a film-to-foam laminatecomprising: contacting a deformable film material with a surface of anopen-cell, flexible, acoustical, polyurethane foam, said film having athickness of from 1/10 mil to 20 mils;adhesively activating with heatthe film material or the surface of the foam; mechanically pressing andembossing the deformable film, at an elevated temperature and pressure,into the surface of the foam with a heated embossing roll having apredetermined embossing pattern of crowns, sidewalls and valleys;controlling the duration of mechanical embossing, the elevatedtemperature and the elevated pressure to result in perforations throughthe film in the sidewalls and valleys caused by pressing the film intothe surface of the foam, said controlling being achieved by maintainingthe heated embossing roll at a temperature of from about 400° F to about600° F and operating the roll at a peripheral speed of from about 8ft/min. to about 100 ft/min., to result in perforations through the filmmaterial having a width of from about 1/50 of an inch to about 1/400 ofan inch; and setting the adhesively activated material to result in thefilm-to-foam laminate.
 2. The method of claim 1 wherein the duration ofmechanical embossing, the temperature and the pressure are controlled toresult in about 30 to about 1500 perforations per square inch oflaminated surface of sufficient size to result in a porosity for thelaminate of from about 3 ft³ /min.-ft² to about 100 ft³ /min.-ft². 3.The method of claim 1 wherein a hydrophobic lubricant and release agentis coated on the film.
 4. The method of claim 3 wherein the hydrophobiclubricant and release agent is applied onto the heated embossing rollwhich contacts the film and coats the film with said agent duringembossing.
 5. The method of claim 3 wherein said agent is dimethylsiloxane.